Railroads are generally constructed of a pair of elongated, substantially parallel rails, which are coupled to a plurality of laterally extending ties via metal tie plates and spikes and/or spring clip fasteners. The rails and ties are disposed on a ballast bed formed of hard particulate material, such as gravel.
During installation of new railroad and maintenance of existing railroad, the ballast adjacent to and/or under the ties is “tamped,” or compressed, to ensure that the ties, and therefore the rails, do not shift. A rail vehicle for carrying out tamping operations is generally referred to as a “tamper” and includes work heads for carrying out tamping operations. Such work heads typically include a number of tamper tools, which each include a pair of elongated, vertically extending tamper arms that terminate in a prong or multiple prongs. The tamper arms and associated prongs are adapted to move towards one another in a pincer-like motion in order to compress the ballast adjacent to and underlying the ties. Vibration of the tamper arms and associated prongs further compresses the ballast. In practice, multiple vibration devices may be employed in order to provide tools for tamping inside and outside the rails as well as forward and aft of the ties. Such tamping operations may be carried out at each tie via a tamper vehicle, which advances along the rails.
Tamper vehicles may stop at each tie to perform tamping operations, or alternatively, tamper vehicles may take the form of a “continuous action” tamper vehicle, which does not stop at each tie, but which rather progresses slowly along the rails in a continuous fashion. Such continuous action tamper vehicles have heretofore employed work heads that operate in unison to perform tamping operations at each tie. That is, the work heads repeatedly translate, or “reciprocate,” along a frame of the rail vehicle during tamping operations. For example, the rail vehicle continues to move along the rails while the tamper tools perform tamping operations. Upon completion of tamping operations at a particular tie, the work heads move forward in unison to the next tie. This process is repeatedly carried out.
However, such continuous action tamper vehicles have drawbacks. During tamping operations, it is quite typical to come upon a misaligned, skewed, or enlarged tie. Because the work heads are required to move in unison, it is likely that at least one of the tamping tools will be deployed into the tie, thus potentially damaging both the tie and the tamping tool. In such circumstances, the tool may need to be replaced, which results in loss of efficiency. Accordingly, systems and methods for overcoming such problems are desired.